1. Field of the Invention
The invention relates to an electric connector in which, when a circuit board having circuit terminals is inserted into a slot formed at the electric connector, connector terminals make electrical contact with the circuit terminals.
2. Description of the Related Art
An example of an electric connector which is called a card edge connector and into which a circuit board on which circuit terminals are formed at an edge is inserted is disclosed in Japanese Utility Model Application Publication No. H5 (1993)-84053, for instance.
In the electric connector disclosed in the publication, a connector housing is designed to have therein terminal spaces vertically formed by two stages, and a slot into which a circuit board is to be inserted, extending from a front of the connector housing and between the upper and lower terminal spaces. Connector terminals are inserted into the upper and lower terminal spaces. Each of the connector terminals has a resilient contact, which extends outwardly through an opening of a corresponding terminal space facing the slot. The resilient contacts of the connector terminals inserted into the upper terminal spaces and the resilient contacts of the connector terminals inserted into the lower terminal spaces face each other, and make resilient contact with electrical conductors formed on surfaces of the circuit board.
Hereinbelow is explained a conventional electric connector with reference to FIG. 14.
As illustrated in FIG. 14, a conventional card edge connector 10x into which a connector 20 having a circuit board P therein is inserted includes a connector housing 110x, and connector terminals 120x to each of which a cable C is connected.
The connector housing 110x is designed to have a slot 111 into which a circuit board P formed in the connector 20 is to be inserted, a circular slot 112 into which a connector housing 21 of the connector 20 is to be inserted, and terminal spaces 113x into which connector terminals 120x are to be inserted. The slot 111 defines a space surrounded by an inner wall 114, and the circular slot 112 defines a space formed between an outer wall 115 and the inner wall 114.
Each of the connector terminals 120x includes a sheath 121x inserted into the terminal space 113x, and a resilient contact 122 formed in the sheath 121x to make physical and electrical contact with a corresponding circuit terminal formed on the circuit board P.
Inserting the circuit board P into the conventional card edge connector 10x, the resilient contact 122 compresses a corresponding circuit terminal formed on the circuit board P, and further, the inner wall 114 of the connector housing 110x situated at a rear of the connector terminal 120x receives a compressive forced acted by the resilient contact 122. Since the connector housing 110x is a resin-molded product, it is influenced by an ambient temperature which may vary between high and low temperatures, resulting in that the inner wall 114 is deformed towards the outer wall 115, and thus, a height H1 of the inner wall 114 is increased up to a height H2, as illustrated in FIG. 15. Accordingly, a gap between the terminal space 113x and the circuit board P is widened around the slot 111. If the terminal space 113x were widened, a gap between the connector terminal 120x and the circuit board P is also widened, and hence, a contact load at which the resilient contact 122 of the connector terminal 120x makes contact with the circuit board P lowers. The lowered contact load brings problems that the stability in electrical contact between the card edge connector 10x and the circuit board P is degraded, specifically, the circuit board P is easily taken off the connector housing 110x, and/or oscillation brings the defectiveness in electrical contact between the circuit board P and the connector terminal 120x. 